SteveH2

see my post at around 15:30 today Yes exactly I was thinking inverters would be all or nuthin, but actually overheating protection makes sense. Can't say for sure when output dropped over how long, but suspect it's sudden because I think I would have noticed. Roof looks fine we can get at it easily. No shade. 14 panels BP brand 180WC, grouped as 10 and 4, Fronius IG30 inverter Thanks

Setup. 14 BP 180WC panels, Fronius IG30 inverter. I managed to find the manual for the inverter online. There was a hint that it can reduce the output if it overheats. I turned it off, gave it 10 minutes, turned it on again, and the output climbed to a plausible level (1300W today). Then sunk down to 400Wish. There is an interior fan which isn't turning. If only the local agent responded to messages Thanks

I wish I knew if it was sudden (but see below). From the display on the inverter. Not an app.

Definitely not, but thanks

Our installations dates from 2009, the installer is no longer in business. On a sunny day it runs at 1500W or more. Now it's dropped to 400Wish. The panels are reasonably clean A local outfit says it will be the inverter (price to replace nearly 2K), but that sounds unlikely to me. Could it be, are there any other possibilities? Thanks